This invention relates to reflector lamps. More particularly, it relates to parabolic aluminized reflector lamps.
Parabolic aluminized reflector (PAR) lamps are known in the lighting art. Ideally, a PAR lamp comprises a completely parabolic-shaped glass shell, which is coated with a reflective aluminum substance to form a parabolic reflector. A wire lamp is disposed within the glass shell. A major drawback of this type of lamp is lumen efficiency. A primary reason for the lack of efficiency is that the lamps are not completely parabolic in shape. Instead, the base of the lamp, referred to herein as the xe2x80x9cnose chamberxe2x80x9d and located at the low point of the parabola, is either completely open or is closed but contains a number of openings. The openings provide portals for connecting electrical leads to the wire lamp, and for an exhaust tube for sealed lamps. Consequently, a significant portion of the base of the parabolic reflector is absent in traditional PAR lamps, thus greatly reducing their efficiently. Because the reflective surface is not a full parabola, some light is either lost in the nose chamber or must be reflected multiple times before it can exit the lamp. Such light loss and multiple reflectivity greatly reduce the efficiency of the lamp.
Thus, it is desired to improve the efficiency of PAR lamps by maximizing the reflective surface of the lamp. It is also desired to improve the efficiency of PAR lamps by modifying the base of the lamp to more completely approximate a parabola, and to minimize the cross-sectional area of the nose portion of the base.
It is also desired to increase the life of PAR lamps by reducing the temperature in the nose chamber.
Finally, it is desired to reduce the risk of short circuit due to contact between the metal leads of the wire lamp and the aluminum reflective coating.
A first embodiment of a reflector lamp is provided comprising a glass shell that has a concave inner surface, an outer surface, and an opening through the base of the glass shell forming a nose portion thereof. The reflector lamp also comprises a reflective coating on the concave inner surface, a wire lamp within the shell, and a heat shield in the mouth of the opening in the base of the glass shell, substantially completing the shape of the concave inner surface.
A second embodiment of a reflector lamp is provided comprising a base, a wire lamp, and a glass shell that has a concave inner surface, an outer surface, and a reflective coating on the inner surface. The glass shell further comprises a bottom having an opening therein, which opening forms the top of a slot disposed within the base. The slot has a major diameter and a minor diameter such that the major diameter is substantially longer than the minor diameter. The wire lamp is disposed within the glass shell, and extends into the slot. A third embodiment of a reflector lamp is provided comprising a glass shell, a wire lamp, and a flange, wherein the glass shell has a concave inner surface, an outer surface, and a reflective coating disposed on the inner surface. A wire lamp is disposed within the glass shell. The flange extends from the outer surface of the glass shell and defines a perimeter of a chamber. An extension of the glass shell extends over the chamber defined by the flange. The extension of the glass shell has an inner surface coated with the reflective coating, and an opening therethrough in communication with the chamber defined by the flange.